Oracle10g中新型层次查询选项简介(1)

create table hier
(
parent varchar2(30),
child varchar2(30)
);
insert into hier values(null,'Asia');
insert into hier values(null,'Australia');
insert into hier values(null,'Europe');
insert into hier values(null,'North America');
insert into hier values('Asia','China');
insert into hier values('Asia','Japan');
insert into hier values('Australia','New South Wales');
insert into hier values('New South Wales','Sydney');
insert into hier values('California','Redwood Shores');
insert into hier values('Canada','Ontario');
insert into hier values('China','Beijing');
insert into hier values('England','London');
insert into hier values('Europe','United Kingdom');
insert into hier values('Japan','Osaka');
insert into hier values('Japan','Tokyo');
insert into hier values('North America','Canada');
insert into hier values('North America','USA');
insert into hier values('Ontario','Ottawa');
insert into hier values('Ontario','Toronto');
insert into hier values('USA','California');
insert into hier values('United Kingdom','England'); 

column child format a40
select level,lpad(' ',level*3)||child child
from hier
start with parent is null
connect by prior child = parent;
LEVEL CHILD
---------- --------------------------
1 Asia
2 China
3 Beijing
2 Japan
3 Osaka
3 Tokyo
1 Australia
2 New South Wales
3 Sydney
1 Europe
2 United Kingdom
3 England
4 London
1 North America
2 Canada
3 Ontario
4 Ottawa
4 Toronto
2 USA
3 California
4 Redwood Shores

column path format a50
select level,sys_connect_by_path(child,'/') path
from hier
start with parent is null
connect by prior child = parent;
LEVEL PATH 
-------- --------------------------------------------
1 /Asia
2 /Asia/China
3 /Asia/China/Beijing
2 /Asia/Japan
3 /Asia/Japan/Osaka
3 /Asia/Japan/Tokyo
1 /Australia
2 /Australia/New South Wales
3 /Australia/New South Wales/Sydney
1 /Europe
2 /Europe/United Kingdom
3 /Europe/United Kingdom/England
4 /Europe/United Kingdom/England/London
1 /North America
2 /North America/Canada
3 /North America/Canada/Ontario
4 /North America/Canada/Ontario/Ottawa
4 /North America/Canada/Ontario/Toronto
2 /North America/USA
3 /North America/USA/California
4 /North America/USA/California/Redwood Shores 

select connect_by_isleaf,sys_connect_by_path(child,'/') path
from hier
start with parent is null
connect by prior child = parent;
CONNECT_BY_ISLEAF PATH
---------------------------------- 

0 /Asia
0 /Asia/China
1 /Asia/China/Beijing
0 /Asia/Japan
1 /Asia/Japan/Osaka
1 /Asia/Japan/Tokyo
0 /Australia
0 /Australia/New South Wales
1 /Australia/New South Wales/Sydney
0 /Europe
0 /Europe/United Kingdom
0 /Europe/United Kingdom/England
1 /Europe/United Kingdom/England/London
0 /North America
0 /North America/Canada
0 /North America/Canada/Ontario
1 /North America/Canada/Ontario/Ottawa
1 /North America/Canada/Ontario/Toronto
0 /North America/USA
0 /North America/USA/California
1 /North America/USA/California/Redwood Shores